Welcome to Logo Tournament, and thank you for a minute of your time. Your product looks great.
Here is my first idea. It incorporates environmental colors, and the ocean, with sun rays to emphasize solar. It shows a "new dawn" in the solar water heating industry.
Please feel free to offer feedback and suggestion.
Also please note that the final vector file will have a removable background...the it can be changed or removed. It will be saved as a transparent if you request it that way.